content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.reactive4javaflow.impl.schedulers;
  
  import hu.akarnokd.reactive4javaflow.*;
  import hu.akarnokd.reactive4javaflow.functionals.AutoDisposable;
  import hu.akarnokd.reactive4javaflow.impl.util.OpenHashSet;
  
  import java.util.Objects;
  import java.util.concurrent.*;
  import java.util.function.Consumer;
  
  public class ScheduledExecutorServiceWorker implements SchedulerService.Worker, Consumer<AutoDisposable> {
  
      protected final ScheduledExecutorService exec;
  
      protected OpenHashSet<AutoDisposable> tasks;
  
      protected volatile boolean closed;
  
      public ScheduledExecutorServiceWorker(ScheduledExecutorService exec) {
          this.exec = exec;
          this.tasks = new OpenHashSet<>();
      }
  
      @Override
      public AutoDisposable schedule(Runnable task) {
          Objects.requireNonNull(task, "task == null");
          WorkerTask wt = new WorkerTask(task, this);
          if (add(wt)) {
              Future<?> f;
              try {
                  f = exec.submit((Callable<Void>)wt);
                  wt.setFutureCanCancel(f);
                  return wt;
              } catch (RejectedExecutionException ex) {
                  accept(wt);
                  FolyamPlugins.onError(ex);
              }
          }
          return SchedulerService.REJECTED;
      }
  
      @Override
      public AutoDisposable schedule(Runnable task, long delay, TimeUnit unit) {
          Objects.requireNonNull(task, "task == null");
          WorkerTask wt = new WorkerTask(task, this);
          if (add(wt)) {
              Future<?> f;
              try {
                  f = exec.schedule((Callable<Void>)wt, delay, unit);
                  wt.setFutureCanCancel(f);
                  return wt;
              } catch (RejectedExecutionException ex) {
                  accept(wt);
                  FolyamPlugins.onError(ex);
              }
          }
          return SchedulerService.REJECTED;
      }
  
      @Override
      public AutoDisposable schedulePeriodically(Runnable task, long initialDelay, long period, TimeUnit unit) {
          Objects.requireNonNull(task, "task == null");
          if (period <= 0L) {
              return SchedulerService.Worker.super.schedulePeriodically(task, initialDelay, period, unit);
          }
          WorkerTask wt = new WorkerTask(task, this);
          if (add(wt)) {
              Future<?> f;
              try {
                  f = exec.scheduleAtFixedRate(wt, initialDelay, period, unit);
                  wt.setFutureCanCancel(f);
                  return wt;
              } catch (RejectedExecutionException ex) {
                  accept(wt);
                  FolyamPlugins.onError(ex);
              }
          }
          return SchedulerService.REJECTED;
      }
  
      protected boolean add(AutoDisposable d) {
          if (!closed) {
              synchronized (this) {
                  if (!closed) {
                      tasks.add(d);
                      return true;
                  }
              }
          }
          return false;
      }
  
      @Override
      public void accept(AutoDisposable d) {
          if (!closed) {
              synchronized (this) {
                  if (!closed) {
                      tasks.remove(d);
                  }
              }
          }
      }
  
      @Override
      public void close() {
          if (!closed) {
              OpenHashSet<AutoDisposable> set;
              synchronized (this) {
                  if (closed) {
                      return;
                  }
                  set = tasks;
                  tasks = null;
                  closed = true;
              }
  
              Object[] o = set.keys();
              for (Object e : o) {
                  if (e != null) {
                      ((AutoDisposable) e).close();
                  }
              }
          }
      }
  }
  